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/*
* linux/mm/remap.c
*
* Copyright (c) 2001 Lineo, Inc. David McCullough <davidm@lineo.com>
* Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org> ref uClinux 2.0
* (C) Copyright 1996 Linus Torvalds
*/
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/shm.h>
#include <linux/mman.h>
#include <linux/swap.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
extern unsigned long askedalloc, realalloc;
/*
* Expand (or shrink) an existing mapping, potentially moving it at the
* same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
*
* MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
* This option implies MREMAP_MAYMOVE.
*
* on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
* hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
*/
unsigned long do_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr)
{
struct vm_list_struct *vml = NULL;
/* insanity checks first */
if (new_len == 0)
return (unsigned long) -EINVAL;
if (flags & MREMAP_FIXED && new_addr != addr)
return (unsigned long) -EINVAL;
for (vml = current->mm->vmlist; vml; vml = vml->next)
if (vml->vma->vm_start == addr)
goto found;
return (unsigned long) -EINVAL;
found:
if (vml->vma->vm_end != vml->vma->vm_start + old_len)
return (unsigned long) -EFAULT;
if (vml->vma->vm_flags & VM_MAYSHARE)
return (unsigned long) -EPERM;
if (new_len > ksize((void *) addr))
return (unsigned long) -ENOMEM;
/* all checks complete - do it */
vml->vma->vm_end = vml->vma->vm_start + new_len;
askedalloc -= old_len;
askedalloc += new_len;
return vml->vma->vm_start;
}
/*
* FIXME: Could do a tradional realloc() in some cases.
*/
asmlinkage unsigned long sys_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr)
{
return -ENOSYS;
}
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